One of the principal equipment components of a coiled tubing unit. The injector head incorporates special profiled chain assemblies to grip the coiled tubing string and a hydraulic drive system that provides the tractive effort for running and retrieving the string from the wellbore. The base of the injector head is secured to the wellhead pressure-control equipment by the stripper assembly mounting system. The gooseneck mounted on top of the injector head feeds the tubing string from the reel around a controlled radius into the injector head.